docs: def calldefs(
              self,
              name=None,
              function=None,
              return_type=None,
              arg_types=None,
              header_dir=None,
              header_file=None,
              recursive=None,
              allow_empty=None):
          """returns a set of :class:`calldef_t` declarations, that are matched
          defined criteria"""
          return (
              self._find_multiple(
                  self._impl_matchers[scopedef_t.calldef],
                  name=name,
                  function=function,
                  decl_type=self._impl_decl_types[
                      scopedef_t.calldef],
                  return_type=return_type,
                  arg_types=arg_types,
                  header_dir=header_dir,
                  header_file=header_file,
                  recursive=recursive,
                  allow_empty=allow_empty)
          )